CN118572813A - A modular reconfigurable supercapacitor energy storage management device - Google Patents

Abstract

The present invention provides a modular reconfigurable supercapacitor energy storage management device, which comprises a supercapacitor module composed of a supercapacitor, a balanced management system (BMS), and a bidirectional DC/DC converter. The switch control unit controls each supercapacitor module to perform charge-discharge cycles and self-recovery in turn. The balanced management system (BMS) maintains voltage balance when the supercapacitor capacitance changes differently. The bidirectional DC/DC converter realizes current sharing control when the supercapacitor branch state is switched. The communication unit can transmit state information such as system voltage, supercapacitor capacitance, internal resistance, and control information such as the number of cycles and cut-off voltage. Human-computer interaction is performed through a computer. The capacity and internal resistance monitoring unit is combined with an alarm unit to issue an alarm after an abnormality is detected. The above arrangement effectively prolongs the service life and use efficiency of the supercapacitor, ensures the safety of the energy storage unit, and adds a charge-discharge current control unit and a temperature acquisition unit to increase the control variables, thereby further prolonging the service life and use efficiency of the supercapacitor.

Description

A modular reconfigurable supercapacitor energy storage management device

Technical Field

The present invention relates to the field of power electronics technology, and in particular to a modular reconfigurable supercapacitor energy storage management device.

Background Art

Supercapacitor is a new type of energy storage element between traditional capacitors and chemical batteries. Compared with conventional energy storage devices, it has the advantages of high charging and discharging efficiency and high energy density. The working environment of supercapacitors is usually harsh, so the actual service life is generally lower than expected. Supercapacitors decay with each use. The increase in the number of cycles is often accompanied by performance degradation and increased aging. In terms of performance parameters, it is specifically manifested as an increase in internal resistance and a decrease in capacitance. Moreover, the rated voltage of a single supercapacitor is low, and it is generally necessary to use supercapacitor modules in series and parallel. At the same time, due to differences in production processes, the capacity of supercapacitors cannot be completely consistent, so the resulting voltage imbalance problem will also seriously affect the service life of supercapacitors.

There are two mainstream solutions to the problem of supercapacitor service life: one is to improve the working environment. Existing studies have shown that the life of supercapacitors is greatly affected by temperature, voltage, and current. The service life can be effectively extended by adjusting system temperature, cut-off voltage, charge and discharge current and other parameters; the second is to add compensating supercapacitors and voltage balancing systems, and achieve voltage equalization control through a balanced management system (Balanced Management System, referred to as BMS). After monitoring the abnormal capacitance and internal resistance of the supercapacitor, the compensating supercapacitor will be put into use to maintain the normal operation of the system. This method will also lead to a reduction in the utilization rate of the supercapacitor.

None of the above solutions take into account the self-recovery effect of the supercapacitor and cannot solve the problem of capacitance drop under high-frequency charge and discharge cycles during use of the supercapacitor.

Summary of the invention

The present invention provides a modular reconfigurable supercapacitor energy storage management device. Combining traditional solutions and taking into account the self-recovery effect of supercapacitors, supercapacitors are organized into supercapacitor modules. By controlling the connection and disconnection of each module, each supercapacitor module is switched between the charge and discharge cycle and the static self-recovery state, thereby effectively increasing the service life and use efficiency of the supercapacitor.

The technical solution to achieve the purpose of the present invention is: a modular reconfigurable supercapacitor energy storage management device, including a supercapacitor energy storage unit, a switch control unit, a voltage regulation unit, a capacity and internal resistance monitoring unit, an alarm unit, a communication unit, a current sharing control unit and a computer;

The supercapacitor energy storage unit includes a plurality of supercapacitor modules, each of which is connected in series in sequence, the input end of the front supercapacitor module is connected to the DC bus, each supercapacitor module includes a plurality of supercapacitor branches, both ends of each supercapacitor branch are connected in parallel, and each supercapacitor branch is sequentially connected with a bidirectional DC/DC converter, a plurality of supercapacitors, a balanced management system (BMS) connected to each supercapacitor, and a branch switch, each supercapacitor module output end is connected to the first module switch input end, each supercapacitor module input end is connected to the second module switch input end, and the second module switch output end is connected to the first module switch output end;

The switch control unit is used to control the branch switch, the first module switch and the second module switch, so that the supercapacitor branches of each supercapacitor module perform charge-discharge cycles and self-recovery in turn;

The voltage regulating unit is used to adjust the cut-off voltage of each supercapacitor charge and discharge cycle. Different voltage conditions can change the self-recovery effect of the supercapacitor. By reasonably setting the cut-off voltage, the service life of the system can be extended.

The capacity and internal resistance monitoring unit is used to monitor the capacity and internal resistance of each supercapacitor module and a single supercapacitor, and terminate the charge and discharge cycle when the capacity is too low or the internal resistance is too high;

The alarm unit is used to send out an alarm when a system abnormality is detected;

The communication unit is used to collect system status information in real time and transmit control instructions;

The inter-module current sharing control unit is combined with the bidirectional DC/DC converter in each supercapacitor module to eliminate the circulating current between the series-connected supercapacitor modules;

The computer is used for human-computer interaction with each unit of the system.

Optionally, the system further includes a charge and discharge current control unit and a temperature acquisition unit.

The charge and discharge current control unit is used to adjust the charge and discharge rate of each supercapacitor module during the cycle, and reasonably set the rate according to the cycle time and load requirements to extend the service life of the system;

The temperature acquisition unit is used to monitor the temperature of each module of the system in real time, and to issue an alarm through the alarm unit when the temperature exceeds or falls below a set threshold.

Compared with the prior art, the present invention has the following beneficial effects:

Compared with the traditional solution, the self-recovery effect of the supercapacitor is taken into consideration. Multiple supercapacitor branches composed of supercapacitors are connected in parallel and then combined with a balanced management system (BMS) and a bidirectional DC/DC converter to form an energy storage unit. The switch control unit controls each supercapacitor module to switch between the two operating states of charge and discharge cycle and self-recovery in turn. The balanced management system (BMS) can maintain voltage balance when the supercapacitor capacitance changes differently. The bidirectional DC/DC converter can realize current sharing control when the supercapacitor branch state is switched. The communication unit can transmit system voltage, supercapacitor capacitance, internal resistance and other state information and control information such as the number of cycles and cut-off voltage. Human-computer interaction is performed through a computer. The capacity and internal resistance monitoring unit combined with the alarm unit can issue an alarm after detecting an abnormality, so that the operator can take corresponding measures in time. The above settings effectively extend the service life of the supercapacitor and improve its utilization efficiency, and also ensure the safety of the energy storage unit. The temperature and current variable control unit is added to further extend the service life of the supercapacitor.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

Figure 1 is a diagram showing the capacity attenuation and self-recovery effect of supercapacitors at 2.9V;

Figure 2 is a diagram showing the increase in internal resistance and self-recovery effect of supercapacitors at 2.9V;

Figure 3 is a diagram showing the capacity attenuation and self-recovery effect of supercapacitors at 2.4V;

Figure 4 is a diagram showing the increase in internal resistance and self-recovery effect of supercapacitors at 2.4V;

FIG5 is a schematic diagram of the architecture of a modular reconfigurable supercapacitor energy storage management device provided by an embodiment of the present disclosure;

FIG6 is an operation flow chart of a modular reconfigurable supercapacitor energy storage management device.

DETAILED DESCRIPTION

Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

The self-healing effect of supercapacitors can be verified by the following experiments:

The cutoff voltages of the two supercapacitors were set to 2.9V and 2.4V respectively, and the supercapacitors were subjected to 150,000 charge and discharge cycles, with a short rest period every 50,000 times. The first rest period was 1 day, and the second was 8 days.

As shown in Figures 1 and 2, under 2.9V conditions, the capacity decay of the two supercapacitors in the first 50,000 charge and discharge cycles was 28.27% and 27.11%, respectively, and the internal resistance increased by 58.10% and 79.74%, respectively. The capacitance decay of the second 50,000 charge and discharge cycles was 18.96% and 19.72%, respectively, and the internal resistance increased by 26.26% and 49.02%, respectively. The capacitance decay of the third 50,000 charge and discharge cycles was 22.16% and 21.83%, respectively, and the internal resistance increased by 69.83% and 78.43%, respectively. When the standing time was 1 day, the capacity could be restored by 18.06% and 18.55%, respectively, and the internal resistance decreased by 20.67% and 35.95%, respectively. When the standing time was 8 days, the capacity could be restored by 22.56% and 22.34%, respectively, and the internal resistance decreased by 73.18% and 84.97%, respectively.

As shown in Figures 3 and 4, under 2.4V conditions, the capacity decay of the two supercapacitors in the first 50,000 charge and discharge cycles was 10.00%, 11.38%, and 11.70%, respectively, and the internal resistance increased by 11.70%, 25.17%, and 23.81%, respectively. The capacity decay of the second 50,000 charge and discharge cycles was 8.30%, 7.67%, and 7.83%, respectively, and the capacitance increased by 30.99%, 24.49%, and 42.86%, respectively. The capacity decay of the third 50,000 charge and discharge cycles was 8.25%, 9.10%, and 8.63%, respectively, and the internal resistance increased by 29.82%, 44.22%, and 36.05%, respectively. When the standing time is 1 day, the capacity can be recovered by 7.5%, 6.55% and 6.84% respectively, and the internal resistance can be reduced by 23.98%, 38.78% and 38.78% respectively. When the standing time is 8 days, the capacity can be recovered by 8.57%, 8.74% and 7.41% respectively, and the internal resistance can be reduced by 37.43%, 27.90 and 45.58% respectively.

Experimental data show that if the supercapacitor is left idle for a period of time after a certain number of cycles, its capacitance and internal resistance will be restored to a certain extent. By using this effect to optimize the system design and combining it with existing methods, the service life of the supercapacitor can be further extended and the utilization rate of the supercapacitor can be improved.

FIG5 is a modular reconfigurable supercapacitor energy storage management device provided by an embodiment of the present disclosure, including a supercapacitor energy storage unit, a switch control unit, a voltage regulation unit, a capacity and internal resistance monitoring unit, an alarm unit, a communication unit, a current sharing control unit and a computer;

The supercapacitor energy storage unit includes n supercapacitor modules, each of which is connected in series in sequence, the input end of the front supercapacitor module is connected to the DC bus, each supercapacitor module includes multiple supercapacitor branches, both ends of each supercapacitor branch are connected in parallel, each supercapacitor branch is sequentially connected with a bidirectional DC/DC converter, multiple supercapacitors, a balanced management system (BMS) connected to each supercapacitor, and a branch switch, each supercapacitor module output is connected to the first module switch input, each supercapacitor module input is connected to the second module switch input, and the second module switch output is connected to the first module switch output;

A switch control unit, used to control the branch switch, the first module switch and the second module switch, so that the supercapacitor branches of each supercapacitor module perform charge-discharge cycles and self-recovery in turn;

The voltage regulating unit is used to adjust the cut-off voltage of each supercapacitor charge and discharge cycle. Different voltage conditions can change the self-recovery effect of the supercapacitor. By reasonably setting the cut-off voltage, the service life of the system can be extended.

The capacity and internal resistance monitoring unit is used to monitor the capacity and internal resistance of each supercapacitor module and a single supercapacitor. When the capacity is too low or the internal resistance is too high, the charge and discharge cycle is terminated.

An alarm unit is used to send out an alarm when a system abnormality is detected;

Communication unit, used for real-time collection and transmission of system status information and control instructions;

The inter-module current sharing control unit is combined with the bidirectional DC/DC converter in each supercapacitor module to eliminate the circulating current between the series-connected supercapacitor modules;

Computer, used for human-computer interaction with each unit of the system;

The charge and discharge current control unit is used to adjust the charge and discharge rate of each supercapacitor module cycle, and reasonably set the rate according to the cycle time and load requirements to extend the service life of the system;

The temperature collection unit is used to monitor the temperature of each module in the system in real time, and issue an alarm through the alarm unit when the temperature exceeds or falls below the set threshold.

The operation process of this system is as follows:

Referring to FIG6 , before the system operates normally, the system first executes an initialization program, and then sets the number of cycles and the cut-off voltage before self-recovery of each module. After completion, the communication unit sends an instruction to the switch control unit, and the system starts to operate. Starting from supercapacitor module #1, the first module switch _S11 of supercapacitor module #1 is turned on, and the second module switch _S12 is turned off. The first module switches S _k1 of the remaining supercapacitor modules are disconnected, and the second module switches S _k2 are turned on (k=2, 3, ..., n), that is, the supercapacitor module #1 controlled by switches S ₁₁ and S ₁₂ enters a self-recovery state, and the remaining supercapacitor modules perform charge and discharge cycles. After the set number of cycles is met, switch S ₁₁ is turned off, switch S ₁₂ is turned on, supercapacitor module 1# ends self-recovery, and performs a charge and discharge cycle. At the same time, switch S ₂₁ is turned on, and switch S ₂₂ is turned off, supercapacitor module 2# ends the charge and discharge cycle and performs self-recovery. After that, each module switches state in turn after meeting the number of charge and discharge cycles. After supercapacitor module #n completes self-recovery, it returns to supercapacitor module 1# to restart the alternating self-recovery and charge and discharge cycle of each module. While the system is running, the operator can perform human-computer interaction through a computer combined with a communication unit connected to each unit of the system. The communication unit can collect system status information in real time and transmit computer instructions to timely regulate the system. Considering the difference between the initial capacitance and capacitance change of each capacitor, the voltage balancing control of the supercapacitor is performed through the balanced management system (BMS). The current balancing control unit is combined with the bidirectional DC/DC converter in each supercapacitor module to eliminate the circulating current between the series supercapacitor modules. At the same time, the capacity and internal resistance monitoring unit monitors the capacity and internal resistance of each supercapacitor module and a single supercapacitor. When the capacity is too low or the internal resistance is too high, the charge and discharge cycle is terminated and an alarm is issued through the alarm unit.

In addition, a charging and discharging current control unit and a temperature collection unit are added to increase the control variables, further effectively extending the service life and utilization efficiency of the supercapacitor.

Claims (2)

1. A modular reconfigurable supercapacitor energy storage management device, characterized in that it includes a supercapacitor energy storage unit, a switch control unit, a voltage regulation unit, a capacity and internal resistance monitoring unit, an alarm unit, a communication unit, a current sharing control unit and a computer; The supercapacitor energy storage unit includes a plurality of supercapacitor modules, each of which is connected in series in sequence, the input end of the front supercapacitor module is connected to the DC bus, each supercapacitor module includes a plurality of supercapacitor branches, both ends of each supercapacitor branch are connected in parallel, and each supercapacitor branch is sequentially connected with a bidirectional DC/DC converter, a plurality of supercapacitors, a balanced management system (BMS) connected to each supercapacitor, and a branch switch, each supercapacitor module output end is connected to the first module switch input end, each supercapacitor module input end is connected to the second module switch input end, and the second module switch output end is connected to the first module switch output end; The switch control unit is used to control the branch switch, the first module switch and the second module switch, so that the supercapacitor branches of each supercapacitor module perform charge-discharge cycles and self-recovery in turn; The voltage regulating unit is used to adjust the cut-off voltage of each supercapacitor charge and discharge cycle. Different voltage conditions can change the self-recovery effect of the supercapacitor. By reasonably setting the cut-off voltage, the service life of the system can be extended. The capacity and internal resistance monitoring unit is used to monitor the capacity and internal resistance of each supercapacitor module and a single supercapacitor, and terminate the charge and discharge cycle when the capacity is too low or the internal resistance is too high; The alarm unit is used to send out an alarm when a system abnormality is detected; The communication unit is used to collect system status information in real time and transmit control instructions; The inter-module current sharing control unit is combined with the bidirectional DC/DC converter in each supercapacitor module to eliminate the circulating current between the series-connected supercapacitor modules; The computer is used for human-computer interaction with each unit of the system. 2. The modular reconfigurable supercapacitor energy storage management device according to claim 1 is characterized in that it also includes a charge and discharge current control unit and a temperature acquisition unit The charge and discharge current control unit is used to adjust the charge and discharge rate of each supercapacitor module during the cycle, and reasonably set the rate according to the cycle time and load requirements to extend the service life of the system; The temperature acquisition unit is used to monitor the temperature of each module of the system in real time, and to issue an alarm through the alarm unit when the temperature exceeds or falls below a set threshold.